T-Mobile announced today that it will throttle LTE data and speeds for users on unlimited plans who illegally use more data than they bought by concealing their tethering.

A small percentage of T-Mobile customers on unlimited 4G LTE plans have been discovered to be gaming the system in order to make their tethering look like smartphone usage.

T-Mobile’s Simple Choice plans offer a set amount of mobile hotspot data (up to seven gigabytes) and include tethering at no extra charge. Making tethering look like smartphone usage allows data-hungry customers to use significantly more 4G LTE tethering than their plan includes, with some people consuming up to two terabytes a month.

Their activities have a “disproportionately negative impact” on other users as these rule-breakers “can compromise the network experience for other T-Mobile customers.” The carrier will now clamp down on those people by starting to throttle their data speeds, especially if the carrier determines that they’re misusing their data to access peer-to-peer file sharing networks.

“We’ve developed technology that can detect these people who choose to break our terms and conditions,” said the company. As per T-Mobile’s updated FAQ page on stopping network abusers, the carrier will enforce its customer terms and conditions.

“We’re first warning these customers that they’re illegally using more data than they bought,” reads the document. “We hope folks will stop on their own so they can keep their current plan.”

To be clear, only those people who are signed up for T-Mobile’s old $70 unlimited plan or the current $80 Simple Choice plan will be affected by the new policy. T-Mobile introduced unlimited nationwide 4G LTE data, with no caps, no overages and no annual contract more than two years ago.

So what happens if folks don’t use their data according to T-Mobile’s terms and conditions? Easy, the carrier will throttle their data speeds so they won’t need to “worry about overages” and move those customers to a plan with one gigabyte of 4G LTE data, tethering included.

“Once they’re on a plan with a set amount of 4G LTE data, it won’t matter what method they use for Smartphone Mobile HotSpot,” reads T-Mobile’s notice.

“Once they use their 4G LTE data bucket, they’ll continue to be able to use data at reduced speeds and still never worry about overages.”

T-Mobile began communicating these changes to customers today.

Chances are you don’t need to worry about the new measures as T-Mobile has discovered that a very small percentage of people who make up a fraction of a percent of its customer base have been gaming the system.